What Are Icons?

Many actions, objects and concepts are represented by the icon, a sort of graphical communication symbol. They are faster, more discerning forms of communication, one example of the epithet that a picture is worth a thousand words. It makes the whole computer experience more enjoyable when the user has something else to look at other than text, besides preserving eyesight, and often makes completing various tasks faster.
Xerox Research Center was actually the first to utilize icons, back in 1970, but icons didn’t become popular until Apple Macintosh and Microsoft Windows started using them. They made new users feel more comfortable and helped them learn new processes. The first icons were very basic and today’s wide application of them in toolbars, menus, in various interfaces and on buttons proves that they’ve come a long way.
The ICO format is used by Windows, but a number of graphic formats are available for icons. Unix uses PNG and Apple Macintosh uses Mac formats. Therefore, most of the time software for editing icons is available for Windows and Apple, but Unix users can make icons from most any graphic.
A very general description of the icon designates it as a square image available in multiple color resolutions and sizes. Size usually ranges from 16×16 pixels to 128×128 pixels, and a limited number of systems also support 512×512-pixel icons. These largest icons were pioneered with the Mac OS Leopard.
Pixel dimensions vary with the operating system you employ. In Windows, icons are images of 16- and 256-gammas or True Color images containing alpha channels. Their sizes are 48×48, 32×32, and 16×16 pixels. True color icons in Windows Vista can have resolutions of up to 256×256 pixels. It’s optional to support icons of 128×128 pixels and 512×512 pixels. Instead of ICO formatting, these icons are stored as PNG files. Windows Mobile is able to use 24×24-pixel icons.
Hopefully, you now have a better grasp of the icon and how it changes from platform to platform. It is basically a visual communication aid to make computer operation more popular by increasing its user friendliness.